mbox series

[v2,0/9] Merge arm64/riscv hugetlbfs contpte support

Message ID 20240508111829.16891-1-alexghiti@rivosinc.com (mailing list archive)
Headers show
Series Merge arm64/riscv hugetlbfs contpte support | expand

Message

Alexandre Ghiti May 8, 2024, 11:18 a.m. UTC 
This patchset intends to merge the contiguous ptes hugetlbfs implementation
of arm64 and riscv.

Both arm64 and riscv support the use of contiguous ptes to map pages that
are larger than the default page table size, respectively called contpte
and svnapot.

The riscv implementation differs from the arm64's in that the LSBs of the
pfn of a svnapot pte are used to store the size of the mapping, allowing
for future sizes to be added (for now only 64KB is supported). That's an
issue for the core mm code which expects to find the *real* pfn a pte points
to. Patch 1 fixes that by always returning svnapot ptes with the real pfn
and restores the size of the mapping when it is written to a page table.

The following patches are just merges of the 2 different implementations
that currently exist in arm64 and riscv which are very similar. It paves
the way to the reuse of the recent contpte THP work by Ryan [1] to avoid
reimplementing the same in riscv.

This patchset was tested by running the libhugetlbfs testsuite with 64KB
and 2MB pages on both architectures (on a 4KB base page size arm64 kernel).

[1] https://lore.kernel.org/linux-arm-kernel/20240215103205.2607016-1-ryan.roberts@arm.com/

Changes in v2:
  - Rebase on top of 6.9-rc3

Alexandre Ghiti (9):
  riscv: Restore the pfn in a NAPOT pte when manipulated by core mm code
  riscv: Safely remove huge_pte_offset() when manipulating NAPOT ptes
  mm: Use common huge_ptep_get() function for riscv/arm64
  mm: Use common set_huge_pte_at() function for riscv/arm64
  mm: Use common huge_pte_clear() function for riscv/arm64
  mm: Use common huge_ptep_get_and_clear() function for riscv/arm64
  mm: Use common huge_ptep_set_access_flags() function for riscv/arm64
  mm: Use common huge_ptep_set_wrprotect() function for riscv/arm64
  mm: Use common huge_ptep_clear_flush() function for riscv/arm64

 arch/arm64/Kconfig                  |   1 +
 arch/arm64/include/asm/pgtable.h    |  56 +++++-
 arch/arm64/mm/hugetlbpage.c         | 291 +---------------------------
 arch/riscv/Kconfig                  |   1 +
 arch/riscv/include/asm/hugetlb.h    |   2 +-
 arch/riscv/include/asm/pgtable-64.h |  11 ++
 arch/riscv/include/asm/pgtable.h    | 153 +++++++++++++--
 arch/riscv/mm/hugetlbpage.c         | 227 ----------------------
 arch/riscv/mm/pgtable.c             |   6 +-
 mm/Kconfig                          |   3 +
 mm/Makefile                         |   1 +
 mm/contpte.c                        | 272 ++++++++++++++++++++++++++
 12 files changed, 480 insertions(+), 544 deletions(-)
 create mode 100644 mm/contpte.c

Comments

Alexandre Ghiti May 8, 2024, 11:32 a.m. UTC | #1 
I should not have unplugged this outlet...Sorry, ignore this series, I'm 
sending a RESEND right away.

On 08/05/2024 13:18, Alexandre Ghiti wrote:
> This patchset intends to merge the contiguous ptes hugetlbfs implementation
> of arm64 and riscv.
>
> Both arm64 and riscv support the use of contiguous ptes to map pages that
> are larger than the default page table size, respectively called contpte
> and svnapot.
>
> The riscv implementation differs from the arm64's in that the LSBs of the
> pfn of a svnapot pte are used to store the size of the mapping, allowing
> for future sizes to be added (for now only 64KB is supported). That's an
> issue for the core mm code which expects to find the *real* pfn a pte points
> to. Patch 1 fixes that by always returning svnapot ptes with the real pfn
> and restores the size of the mapping when it is written to a page table.
>
> The following patches are just merges of the 2 different implementations
> that currently exist in arm64 and riscv which are very similar. It paves
> the way to the reuse of the recent contpte THP work by Ryan [1] to avoid
> reimplementing the same in riscv.
>
> This patchset was tested by running the libhugetlbfs testsuite with 64KB
> and 2MB pages on both architectures (on a 4KB base page size arm64 kernel).
>
> [1] https://lore.kernel.org/linux-arm-kernel/20240215103205.2607016-1-ryan.roberts@arm.com/
>
> Changes in v2:
>    - Rebase on top of 6.9-rc3
>
> Alexandre Ghiti (9):
>    riscv: Restore the pfn in a NAPOT pte when manipulated by core mm code
>    riscv: Safely remove huge_pte_offset() when manipulating NAPOT ptes
>    mm: Use common huge_ptep_get() function for riscv/arm64
>    mm: Use common set_huge_pte_at() function for riscv/arm64
>    mm: Use common huge_pte_clear() function for riscv/arm64
>    mm: Use common huge_ptep_get_and_clear() function for riscv/arm64
>    mm: Use common huge_ptep_set_access_flags() function for riscv/arm64
>    mm: Use common huge_ptep_set_wrprotect() function for riscv/arm64
>    mm: Use common huge_ptep_clear_flush() function for riscv/arm64
>
>   arch/arm64/Kconfig                  |   1 +
>   arch/arm64/include/asm/pgtable.h    |  56 +++++-
>   arch/arm64/mm/hugetlbpage.c         | 291 +---------------------------
>   arch/riscv/Kconfig                  |   1 +
>   arch/riscv/include/asm/hugetlb.h    |   2 +-
>   arch/riscv/include/asm/pgtable-64.h |  11 ++
>   arch/riscv/include/asm/pgtable.h    | 153 +++++++++++++--
>   arch/riscv/mm/hugetlbpage.c         | 227 ----------------------
>   arch/riscv/mm/pgtable.c             |   6 +-
>   mm/Kconfig                          |   3 +
>   mm/Makefile                         |   1 +
>   mm/contpte.c                        | 272 ++++++++++++++++++++++++++
>   12 files changed, 480 insertions(+), 544 deletions(-)
>   create mode 100644 mm/contpte.c
>
Andrew Morton May 8, 2024, 4:27 p.m. UTC | #2 
On Wed,  8 May 2024 13:18:20 +0200 Alexandre Ghiti <alexghiti@rivosinc.com> wrote:

> This patchset intends to merge the contiguous ptes hugetlbfs implementation
> of arm64 and riscv.
> 
> ...
> 
>  arch/arm64/Kconfig                  |   1 +
>  arch/arm64/include/asm/pgtable.h    |  56 +++++-
>  arch/arm64/mm/hugetlbpage.c         | 291 +---------------------------
>  arch/riscv/Kconfig                  |   1 +
>  arch/riscv/include/asm/hugetlb.h    |   2 +-
>  arch/riscv/include/asm/pgtable-64.h |  11 ++
>  arch/riscv/include/asm/pgtable.h    | 153 +++++++++++++--
>  arch/riscv/mm/hugetlbpage.c         | 227 ----------------------
>  arch/riscv/mm/pgtable.c             |   6 +-
>  mm/Kconfig                          |   3 +
>  mm/Makefile                         |   1 +
>  mm/contpte.c                        | 272 ++++++++++++++++++++++++++
>  12 files changed, 480 insertions(+), 544 deletions(-)
>  create mode 100644 mm/contpte.c

Hits three subsystems, so I guess mm.git is the place.  I'll await
reviewer/tester input and let's look at getting this into mm.git after
6.10-rc1?
Alexandre Ghiti May 8, 2024, 6:25 p.m. UTC | #3 
Hi Andrew,

On 08/05/2024 18:27, Andrew Morton wrote:
> On Wed,  8 May 2024 13:18:20 +0200 Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
>
>> This patchset intends to merge the contiguous ptes hugetlbfs implementation
>> of arm64 and riscv.
>>
>> ...
>>
>>   arch/arm64/Kconfig                  |   1 +
>>   arch/arm64/include/asm/pgtable.h    |  56 +++++-
>>   arch/arm64/mm/hugetlbpage.c         | 291 +---------------------------
>>   arch/riscv/Kconfig                  |   1 +
>>   arch/riscv/include/asm/hugetlb.h    |   2 +-
>>   arch/riscv/include/asm/pgtable-64.h |  11 ++
>>   arch/riscv/include/asm/pgtable.h    | 153 +++++++++++++--
>>   arch/riscv/mm/hugetlbpage.c         | 227 ----------------------
>>   arch/riscv/mm/pgtable.c             |   6 +-
>>   mm/Kconfig                          |   3 +
>>   mm/Makefile                         |   1 +
>>   mm/contpte.c                        | 272 ++++++++++++++++++++++++++
>>   12 files changed, 480 insertions(+), 544 deletions(-)
>>   create mode 100644 mm/contpte.c
> Hits three subsystems, so I guess mm.git is the place.  I'll await
> reviewer/tester input and let's look at getting this into mm.git after
> 6.10-rc1?


Sure, fine by me :)

Thanks,

Alex


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